Its different from network to network, while you are right very few if any will promote you, they offer you other things to help you grow your channel, also networks that have good ad sales team can significantly increase your CPM which will result in you earning more even after their cut which is why its best to research into what sort of CPM's your going to be receiving for when you move to the network you want.
Being partnered with RPM will definitely not result in a huge boost in views/subs if any boost at all. They give you tools to help you but they very rarely if ever promote your channel (you have to be extremely luck to be featured) and even when they do it does not significantly help you in terms of views, views/subs are reliant on you promoting your channel and not the network.[DOUBLEPOST=1365708411,1365708322][/DOUBLEPOST]
Without going into specifics, are you happy with your CPM with fullscreen?